plugins.php

• URL: /wp-admin/plugins.php
• Capability required: activate_plugins (and related caps like deactivate_plugins, delete_plugins, update_plugins).
• What it does: Lists installed plugins, handles activation/deactivation, deletion, auto-updates, and plugin bulk actions.
• Key hooks: activate_{$plugin}, pre_current_active_plugins, all_plugins, handle_bulk_actions-{$screen}.

plugin-install.php

• URL: /wp-admin/plugin-install.php
• Capability required: install_plugins (plus upload_plugins for upload tab).
• What it does: Plugin installer UI (search, featured, upload) and installs plugins from WordPress.org or zip uploads.
• Key hooks: install_plugins_pre_{$tab}, install_plugins_{$tab}, install_plugins_upload, install_plugins_pre_upload.

plugin-editor.php

• URL: /wp-admin/plugin-editor.php
• Capability required: edit_plugins.
• What it does: Built-in plugin file editor.
• Key hooks: (none in file; standard admin hooks apply).